This application claims the priority of German Application No. 199 22 324.6, filed in Germany on May 14, 1999, the disclosure of which is expressly incorporated by reference herein.
The invention relates to a heating or air-conditioning system for a vehicle occupant compartment having an air distributor with a warm-air outlet which is connected with an air duct leading to air outlet devices arranged in a center plane of the vehicle occupant compartment, and having a cold-air bypass controlled by a cold-air flap, for lowering the temperature of warm air flowing out of the warm air outlet to the air duct.
In the case of a known air-conditioning system of this type for motor vehicles (German Patent Document DE 32 03 424 C), on the one side, a warm-air flap is arranged at the warm-air outlet and, and on the other side, a cold-air flap is arranged at the inlet of the cold-air bypass for controlling the temperature of the air flowing into the center plane of the vehicle occupant compartment. The warm-air flap divides the air flowing out of the warm-air outlet into two warm-air flows, of which one is guided to an air duct leading to the center plane of the vehicle occupant compartment and the other is guided to an air duct leading to the leg space of the vehicle occupant compartment. By means of a more or less extensive opening of the cold-air flap, cold air can be admixed to the warm-air flow branched off to the center plane, so that a desired temperature of the mixed air is obtained. For setting the temperature in the center plane, the two air flaps are controlled separately, in which case, for keeping the air quantity constant which flows into the center plane, the warm-air flap is increasingly closed as the opening of the cold-air flap increases. In the case of the known air-conditioner, this type of flap control necessarily leads to an increase of the warm-air quantity flowing into the leg space, so that, for avoiding this effect, it is again absolutely necessary to provide an additional cold-air and warm-air flap for controlling the air flowing into the leg space.
In the case of a heating or air-conditioning system of this type (German Patent Document DE 198 51 982.6), it has been suggested, for the purpose of a simplified automatic temperature control for the center plane of the vehicle occupant compartment and for the manual temperature reduction in the center plane, to arrange a so-called center plane air flap for controlling the duct cross-section in the air duct leading to the air outflow devices in the center plane of the vehicle occupant compartment and to forcibly couple the center plane air flap with the cold-air flap of the cold-air bypass such that, for a maximal heating, the cold air flap and the center plane air flap are closed; for the automatic control of the air quantity to the center plane, the cold-air flap is closed; and the center plane flap is opened up corresponding to the desired air quantity and, for lowering the temperature in the center plane, the automatic center nozzle key is unlocked and, by rotating an operating element, the cold-air flap is correspondingly manually opened. In the case of such a heating or air-conditioning system, it is problematic that, while the cold-air bypass has a space-related small design, a desired maximal temperature reduction of, for example, 400xc2x0 K. in the center plane of the vehicle occupant compartment is not reached.
It, is an object of the invention to improve a heating or air-conditioning system of the initially mentioned type such that, also when the cross-sectional design of the cold-air bypass is small as the result of the limited space, a sufficient lowering of the temperature is achieved in the center plane.
According to the invention, this object is achieved by providing a system of the above-noted general type, wherein a throttling element is coupled with the cold-air flap such that in one end position the throttling element partially covers the warm-air outlet to a defined extent in an open position of the cold-air flap, which maximally opens up the cold-air bypass. In a second end position of the throttling element, the throttling element completely opens the warm air outlet up in a closed position of the cold-air flap, which completely blocks the cold-air bypass. The throttling element moves continuously between these two end positions with the swiveling of the cold-air flap.
The heating or air-conditioning system according to the invention has the advantage that, as the result of the throttling element which, when the cold-air flap is fully opened, swivels or pushes into the warm-air outlet of the air distributor, the warm-air flow is throttled downstream of the bypass mouth. As a result, less warm air enters into the air duct leading to the center plane. Simultaneously, by way of the throttling element, which increasingly covers the warm-air outlet to a defined maximal extent, the air flow to the air duct leading to the center plane becomes increasingly more diffuse as the center plane temperature becomes colder. Accordingly, the approaching air flow by way of colder air is perceived to be more comfortable by the occupants of the vehicle occupant compartment and thus causes an increase of the air-conditioning comfort.
Advantageous embodiments of the heating or air-conditioning system with expedient developments and further developments of the invention are described herein and in the claims.
According to alternative embodiments of the invention, the movable throttling element can be constructed as a swivel flap, a slide or an air guiding element in the form of a curved two-blade swivel flap. In addition, in order to avoid additional air noise, the throttling element can be enclosed by a foamed material, a foamed material can be sprayed around it or it can be foamed in by way of a foamed material. A perforation in the slide or flap surface of the throttling element reduces the throttling effect. By means of an appropriate selection of the hole grid and of the hole diameter, the throttling effect can be adapted in an extremely precise manner.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.